Cutter bit



April 1, 1970 D. R. VAUGHAN ETAL 3,507,345

CUTTER BIT Filed Nov. 5. 1967 INVENTOR. DONALD R. VAUGHAN CARL J. FALCON W am ' ATTO RN EYS United States Patent 3,507,345 CUTTER BIT Donald R. Vaughan and Carl J. Falcon, Woodland, Calif., assignors to Woodland Manufacturing Company, Woodland, Calif., a corporation of California Filed Nov. 3, 1967, Ser. No. 680,488 Int. Cl. E21c 13/00; F161 1/00 US. Cl. 175413 9 Claims ABSTRACT OF THE DISCLOSURE The present invention relates to improvements in cutting tools and, more particularly, to an improved cutter bit of the type adapted for earth-cutting operations.

The present invention is directed to an improved cutter tool or cutter bit of the type used for cutting the earth when it is secured to and extends outwardly from a rotatable shaft. The cutter bit itself has a relatively rigid body provided with a leading cutting edge and a front face terminating at the cutting edge and extending away therefrom. The cutter bit is provided with an arcuate, normally innermost end surface which is adapted to be complementally secured to the outer cylindrical surface of a rotatable shaft whereby the cutting edge and the front face extends completely to the shaft itself. Means is provided for removably mounting the cutter bit on the shaft and, to this end, the mounting means includes a holding device adapted to removably and frictionally receive a mounting stem integral with the cutter bit itself. The holding device is adapted to be rigidly secured to and to follow the contour of the outer surface of the shaft so that the cutter bit can be mounted relative to the shaft in the manner described above.

The cutter bit has an outer portion adapted to cut into the earth as the shaft rotates. One embodiment of the cutter bit utilizes this outer portion in angularly disposed relationship to the inner portion of the bit, whereby earth cut by the outer porton is directed toward the inner portion of the bit. This type of cutter bit is adapted for cutting adobe and aggregate. A second embodiment of the invention provides for a relatively straight cutting edge throughout the length of the cutter bit itself with the front face of the same being divided into two sections which are in different planes with respect to each other. This embodiment is adapted for soils other than those for which the angled cutter bit is used.

In a particular type of earth-cutting apparatus a number of cutter bits or cutting tools are rigidly secured to and project outwardly from the outer surface of a rotatable, tubular shaft. The shaft moves transversely through the earth to provide a non-trenching means of laying cable below the surface of the earth. The cable is directed through the shaft and is laid below ground level as the shaft rotates and the cutter bits cut through the earth.

The cutter bits are arranged relative to each other about the shaft in a manner to assure that the earth that is cut by each cutter bit is prevented from building up on the cutting edges of successive cutter bits to thereby avoid the clogging or jamming of earth in and about the rotating shaft itself. In this way, the apparatus is highly efiicient and avoids the problems of the prior art which 3,507,345 Patented Apr. 21, 1970 clog or jam with soil in these areas so that operation of the apparatus becomes very difiicult when this soil buildup begins. Thus, it is highly desirable that the circulation of earth cut by the cutter bits be as smooth as possible rearwardly of the shaft as the latter rotates and moves forwardly. Thus, the apparatus will operate without interruption so as to avoid costly shut-down time required for conventional apparatus to clean the cutter tool.

Even though the cutter bits described above are highly satisfactory for their intended purpose, the cutter bits do not have earth-cutting portions which extend to the shaft itself. Thus, the cutting action of the cutter bits is not what it could be. Also, the base portions of the cutter bits jut out from the shaft and have a slight tendency to cause the soil to adhere to the shaft at locations adjacent to the roots of the cutter bits.

The present invention is directed to a cutter bit which improves upon the cutter bits described above by providing a structure which substantially minimizes or eliminates the soil build-up at the root of a cutter 'bit. Also the cutter bit of this invention has a cutting portion which extends completely to the shaft itself. In this way, not only is the cutting action of the cutter bit increased but soil will have very little chance to adhere to the shaft or the root of a cutter bit and thus will circulate freely past the shaft as the latter moves forwardly. This feature substantially improves the overall circulation of the soil with respect to the shaft to thereby increase the efficiency of the cutting apparatus itself by assuring that the apparatus will operate continuously without interruption.

Another advantage of the present invention is the way in which each cutter bit is mounted on the shaft. To this end, each cutter bit is provided with a rearwardly extending mounting stern which is removably received within the wedge-shaped interior of a holding device whose cross-section is transversely U-shaped and whose outer edges are adapted to be rigidly secured or otherwise affixed to the outer surface of the shaft. In this way, the cutter bits can be removed from the shaft and replaced when they become worn notwithstanding the fact that the cutter bits themselves extend completely to the shaft to prevent the aforesaid build-up of soil on the shaft itself.

A further advantage of the present invention is the provision of an outer cutting portion of the cutter bit which can be selected in accordance with the make-up of the type of soil to be cut. This feature provides for greater versatility for the basic configuration of the cutter bit without affecting the circulation of the severed soil past the shaft.

It is therefore the primary object of this invention to provide an improved cutter bit which is adapted to be mounted on the outer surface of a rotatable shaft, wherein the cutting portion of the cutter bit extends to the shaft itself not only to provide for optimum cutting action, but also to prevent the buildup of soil at the junction between the cutter bit and the shaft.

Another object of this invention is to provide a cutter bit of the type described wherein the inner extremity of the cutter bit has an arcuate surface complemental to the outer surface of the rotatable shaft with the leading cutting edge of the cutter bit extending inwardly to the shaft to thereby permit the cutting portion of the cutter bit to extend outwardlv from the shaft and thereby be effective to augment the circulation of earth past the shaft as the latter moves forwardly.

Still another object of this invention is to provide a cutter bit of the aforesaid character wherein the outer cutter portion of the cutter bit is constructed to effectively sever different types of soil without departing from the advantages of optimum cutting action and the substantial elimination of soil build-up at the root of the cutter bit.

A further object of this invention is to provide a cutter bit for a rotatable shaft wherein an improved tool holding device is secured to the outer surface of the shaft and removably mounts the cutter bit thereon to thereby allow for quick replacement of the cutter bit without impairing the circulation of the soil past the cutter bit and the holding device itself.

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawing for several embodiments of the cutter bit.

In the drawing:

FIG. 1 is a top plan view of a first embodiment of the cutter bit and a holding device therefor;

FIG. 2 is a cross-sectional view taken along line 22 on the holding device of FIG. 1;

FIG. 3 is an end elevational view of the cutter bit of FIG. 1;

FIG. 4 is a rear elevational view of the same;

FIG. 5 is a view similar to FIG. 1 but illustrating a second embodiment of the cutter bit;

FIG. 6 is an end elevational view of the cutter bit of FIG. 5; and

FIG. 7 is a rear elevational view of the cutter bit of FIGS. 5 and 6.

The first embodiment of the cutter bit of this invention is broadly denoted by the numeral 10 and includes a body 12 of generally rigid material having a leading cutting edge 14 and a front face 16 terminating at and extending away from leading edge 14. Cutter bit 10 has normally innermost, arcuate end surface 18 which converges to leading edge 14 at point 20 (FIG. 1).

Front face 16 is divided into an inner section 22 and an outer section 24. These sections have different inclinations and are connected by a generally triangular area or step 26 with sections 22 and 24 merging substantially smoothly with step 26. Section 22 has a trailing edge 28 and section 24 has a trailing edge 30 which is normally forwardly of trailing edge 28 as shown in FIG. 1. The location of trailing edge 30 is due to the fact that sections 22 and 24 are in different planes. Trailing edge 30 has a substantially rounded contour at 32 which merges smoothly with a normally upper generally flat surface 34 which terminates at an edge 36 which is substantially coextensive with trailing edge 28 (FIG. 1).

Body 12 is provided with generally rectangular crosssection in the vicinity of section 24, as shown in FIG. 3. The body also has a substantially triangular cross-section in the vicinity of section 22. This triangular cross-section defines a substantially fiat rear face 38 opposed to front face 16 and extending perpendicularly to the generally fiat bottom surface 40 of body 12 beneath inner section 22.

A mounting stem 42 is integral with flat face 38 and extends outwardly therefrom in the manner shown in FIGS. 1 and 3. Stem 42 has a concave side surface 44, which is co-extensive with end surface 18 and has a convex end surface 46 opposed to and relatively convergent with side surface 44. Thus, stem 42 has a wedge-shaped configuration and is adapted to be received within the wedge-shaped recess or interior 48 of a transversely U- shaped holding device 50 whose opposed outer edges 52 are substantially complemental to end surface 44. Holding device 50 has a pair of sides 54 which are adapted to frictionally engage the opposite sides of stem 42 for removably holding cutter bit 10 in a fixed position relative to rotatable structure hereinafter described. FIG. 4 illustrates how holding device 50 receives stem 42 while side surface 44 and edges 52 are substantially co-extensive with end surface 18. FIG. 4 further illustrates that the normally uppermost side 54 of holding device 50 will be at least substantially flush with or below trailing edge 28. Thus, device 50 will not present an abutment which would hinder the desired circulation of soil or would allow soil build-up in this area.

In use, cutter bit 10 is adapted to be secured to a ro- 4 tatable shaft broadly denoted by the numeral 56 and shown in dashed lines in FIG. 1. To this end, holding device 50 is secured at edges 52 to the cylindrical outer surface 58 of shaft 56 so that mounting stem 42 can be removably inserted in recess 48 and frictionally held by device 50.

When device 50 is secured to surface 58, edges 52 will be complemental to and extend along an arcuate portion of surface 58 and will mount cutter bit 10 so that both end surface 18 and side surface 44 will complementally engage outer surface 28 in the manner shown in FIG. 1. In this way, leading edge 14 and front face section 22 will extend completel to shaft 56 so that there will be no discontinuity in the cutting portion of the cuter bit due to the mounting of the latter on the shaft.

The outer face section 24 provides a rugged cutting portion for the cutting bit and is constructed to assure that the circulation of the material past the cutter bit will be essentially uninterrupted while preventing roots or the like from balling up the cutter bit. The reduced inclination of section 22 relative to section 24 allows the smooth circulation or flow of earth past the cutter bit so that the soil will not adhere to the outer surface 58 of shaft 56 nor to the cutter bit and the holding device.

A second embodiment of the cutter bit of the invention is broadly denoted by he numeral and includes a body 112 having a cutting edge 114 and a front face 116 terminating at and extending away from leading edge 114. Cutter bit 110 has an innermost peripheral end surface 118 which is arcuate in the same manner as surface 18 of cutter bit 10. End surface 118 converges to leading edge 114 at point 120 (FIG. 5).

Front face 116 is divided into a pair of angularly disposed sections 122 and 124 which merge smoothly with each other at a concave area 126. Section 122 has a trailing edge 128 and section 124 has a trailing edge 130 which extends at an angle relative to trailing edge 128. Similarly, cutting edge 114 has a first segment 114a and a second segment 11412 which is angularly dispose-d relative to segment 114a.

Body 112 has a generally rectangular cross-section in the vicinity of section 124 as shown in FIGS. 6 and 7. In the vicinity of section 122, the body has a generally triangular cross-section to present a generally flat rear face 138 perpendicular to the bottom surface 140 beneath section 122. A mounting stem 142 projects outwardly from flat rear face 138 and has an inner, arcuate side surface 144 substantially co-extensive with end surface 118 (FIG. 5). The opposite side 146 of stem 142 is convex and is relatively convergent with respect to side surface 114 so that stem 142 has a substantially wedge-shaped configuration in the same manner as stem 42 of cutter bit 10. By virtue of this construction, cutter bit 110 can utilize holding device 50 for mounting to a shaft 156 having a cylindrical outer surface 158.

In use, cutter bit 110 is utilized with a holding device 50 wherein the holding device is rigidly secured to the cylindrical outer surface 158 of a shaft 156. Mounting stem 142 is frictionally and removably received within holding device 50 so that end surface 118 and side surface 144 will be in juxtaposition to and extend complementally about a circumferential portion of outer surface 158. Thus, leading edge 114 and front face section 122 extend completely to shaft 156. The cutter bit will, therefore, present no discontinuity at the junction between it and the shaft, whereby circulation of soil or other materials will be unimpeded to thereby assure efficient operation for the cutting apparatus of which cutter bit 110 forms a part.

The outer cutting portion defined by face section 124 is constructed to direct loosened or displaced soil inwardly toward section 122, whereupon the soil is moved smoothly and rearwardly up the cutter bit so as not to build up on the cutter bit itself or at the junction of the cutter bit and the shaft. Cutter bit 110 is especially adapted for soil such as adobe and aggregate; whereas, cutter bit is adapted for use with other types of soils, especially those having roots.

When it is desired to replace the cutter bit, it can be removed by forcing stem 142 out of device 50, whereupon a new cutter bit can be mounted in the same manner as described above.

While several embodiments of this invention have been shown and described, it will be apparent that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

1. A cutter bit for rotatable shaft having a cylindrical outer surface comprising: a body formed of a rigid material and having a leading cutting edge, a normally front face terminating at and extending away from said leading edge, and an arcuate peripheral end surface substantially complemental to the outer surface of the shaft, said cutting edge being convergent to said end surface and forming an acute angle with the portion thereof adjacent to the cutting edge, said body adapted to be secured to said shaft with said front face inclined with respect to the longitudinal axis thereof and with said surface in juxtaposition to said outer surface of the shaft.

2. A cutter bit as set forth in claim 1, wherein said body has a rear face substantially opposed to said front face, and wherein is included a stem extending outwardly from said rear face to present structure for mounting said body on the shaft.

3. A cutting tool for a rotatable shaft having a cylindrical outer surface comprising: a cutter bit having an arcuate, normally innermost end surface, a leading cutting edge, and a front face terminating at and extending away from said cutting edge, said front face and said cutting edge extending laterally from said end surface, the latter being substantially complemental to said outer surface of the shaft, the portion of said arcuate end surface adjacent to said front face being convergent to said cutting edge and forming an acute angle therewith; and means adapted to be secured to said shaft for removably mounting the cutter bit thereon with said end surface in substantial juxtaposition to said outer surface of the shaft.

4. A cutting tool as set forth in claim 3, wherein said cutter bit having a mounting stem secured thereto and extending outwardly therefrom, said mounting means including structure for attachment to said outer surface of the shaft and having a recess for frictionally receiving said mounting stem.

5. In a cable laying device for the non-trenching placement of cable beneath the earths surface of the type having a tubular, cylindrical tool-holding member and means for rotating the tool-holding member in a predetermined direction as the same is moved transversely through the surface of the earth, the improvement comprising: a cutter tool adapted to be secured to said toolholding member and to extend laterally therefrom, said cutter tool having a leading cutting edge, a front face terminating at and extending away from said cutting edge, and an arcuate, peripheral end surface substantially complemental to the outer surface of said tool-holding member; a mounting stem secured to and extending rearwardly from said tool with reference to the forward direction of rotation of said tool-holding member at a location spaced from said front face; and means adapted to be secured to the outer surface of the tool-holding member for removably receiving said stem thereto with the end surface of said tool in substantial juxtaposition to said outer surface of the tool-holding member and with said front face inclined relative to the longitudinal axis of the tool holding member.

6. A cutter bit for a rotatable shaft having a cylindrical outer surface comprising: a body formed of a rigid material and having a leading cutting edge, a normally front face terminating at and extending away from said leading edge, and an arcuate peripheral end surface substantially complemental to the outer surface of the shaft, said body adapted to be secured to said shaft with said front face inclined with respect to the longitudinal axis thereof and with said end surface in juxtaposition to said outer surface of the shaft, said body having a pair of sections, one section being adjacent to said end surface, the other section being remote from said end surface and disposed at an angle with respect to said one section, the other section having a front face portion at least partially facing in the direction of said end surface, whereby earth dislodged by the other section will be directed toward said one section.

7. A cutter bit for a rotatable shaft having a cylindrical outer surface comprising: a body formed of a rigid material and having a leading cutting edge, a normally outermost end, a normally front face terminating at and extending away from said leading edge, and an arcuate peripheral end surface substantially complemental to the outer surface of the shaft, said cutting edge being substantially straight from said end surface to said outermost end, said front face having an inner section and an outer section, each of said sections being substantially flat, the outer section being out of the plane of the inner section, said body adapted to be secured to said shaft with said front face inclined with respect to the longitudinal axis thereof and with said end surface in juxtaposition to said outer surface of the shaft.

8. A cutting tool for a rotatable shaft having a cylindrical outer surface comprising: a cutter bit having an arcuate, normally innermost end surface, a leading cutting edge, and a front face terminating at and extending away from said cutting edge, said front face and said cutting edge extending laterally from said end surface, the latter being substatnially complemental to said outer surface of the shaft; a transversely U-shaped holding device having a pair of spaced, arcuate edges adapted to be secured to and to extend along said outer surface of the shaft; and a mounting stern on said cutter bit, said stern being removably and frictionally received within said device with one extremity of the stem being substantially complemental and in proximity to said outer surface of the shaft and with said end surface in substantial juxtaposition to said outer surface of the shaft.

9. A cutting tool as set forth in claim 8, wherein the cutter bit has a rear face and a trailing edge, said stem projecting outwardly from said rear face, said device being aligned with the area between the leading and trailing edges and being at least substantially flush with said trailing edge.

References Cited UNITED STATES PATENTS 2,417,313 3/1947 MacKinnon 6l-72.6 2,815,192 12/1957 Parrish 394 3,354,660 11/1967 Vaughan 37-81 X JACOB SHAPIRO, Primary Examiner US. 01. X.R. 

